Hi Alex,
thanks for having a look!
On 21/11/16 15:34, Alexander Graf wrote:
On 20/11/2016 15:56, Andre Przywara wrote:
For boards that call s_init() when the SPL runs, we are expected to setup an early stack before calling this C function. Implement the proper AArch64 version of this based on the ARMv7 code. This allows sunxi boards to setup the basic peripherals even on with a 64-bit SPL.
Signed-off-by: Andre Przywara andre.przywara@arm.com
Isn't that what _main in ./arch/arm/lib/crt0_64.S is supposed to do? That should be used for the SPL flow too, no?
I saw that too, but apparently this one here is a some shortcut for the SPL. TBH I didn't dare to look too closely, as this seems to be a bit entangled.
....
arch/arm/cpu/armv8/Makefile | 1 + arch/arm/cpu/armv8/lowlevel_init.S | 44 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) create mode 100644 arch/arm/cpu/armv8/lowlevel_init.S
diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile index dea1465..799a752 100644 --- a/arch/arm/cpu/armv8/Makefile +++ b/arch/arm/cpu/armv8/Makefile @@ -25,3 +25,4 @@ obj-$(CONFIG_FSL_LAYERSCAPE) += fsl-layerscape/ obj-$(CONFIG_S32V234) += s32v234/ obj-$(CONFIG_ARCH_ZYNQMP) += zynqmp/ obj-$(CONFIG_TARGET_HIKEY) += hisilicon/ +obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o diff --git a/arch/arm/cpu/armv8/lowlevel_init.S b/arch/arm/cpu/armv8/lowlevel_init.S new file mode 100644 index 0000000..189e35f --- /dev/null +++ b/arch/arm/cpu/armv8/lowlevel_init.S @@ -0,0 +1,44 @@ +/*
- A lowlevel_init function that sets up the stack to call a C
function to
- perform further init.
- SPDX-License-Identifier: GPL-2.0+
- */
+#include <asm-offsets.h> +#include <config.h> +#include <linux/linkage.h>
+ENTRY(lowlevel_init)
- /*
* Setup a temporary stack. Global data is not available yet.*/+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
- ldr w0, =CONFIG_SPL_STACK
+#else
- ldr w0, =CONFIG_SYS_INIT_SP_ADDR
+#endif
- bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */
- /*
* Save the old LR(passed in x29) and the current LR to stack*/- stp x29, x30, [sp, #-16]!
- /*
* Call the very early init function. This should do only the* absolute bare minimum to get started. It should not:** - set up DRAM* - use global_data* - clear BSS* - try to start a console** For boards with SPL this should be empty since SPL can do all of* this init in the SPL board_init_f() function which is called* immediately after this.So this comment says that s_init shouldn't even be used for SPL and instead we should use board_init_f which is what crt0 calls.
Yes, that is a good point. So the sunxi port seemed to ignore this recommendation and do it in its own way (TM). Frankly I didn't want to fix this one too at this point, so I just went ahead with filling the 64-bit gaps. But I agree that this should be fixed eventually. The line above: +obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o hints already that something is not really right here, as SUNXI is the only user of this rather generic function. If I find some spare time (haha), I might take a look, otherwise: be my guest ;-)
Cheers, Andre.